Main menu

Post navigation

Avoiding Mistakes

People often treat mistakes as unavoidable. Or sometimes people think mistakes are made because the person making them is unfamiliar with the situation or environment.

The truth is far more complex and often mistakes are not only avoidable, but they’re a direct result of the person being overly familiar with the situation or environment.

A post that came across my desk the other day discusses the Normalization of Deviance. No, I’m not talking about how references to 50 Shades of Grey are all over the place. I’m talking about how we come to accept errors as “ok” or even normal.

A classic example of this are the cases of O-ring burnthrough on flights prior to the Challenger disaster. The original specs called for no burnthrough. Any burnthrough was not acceptable. Yet once it was observed the basic attitude was that it hadn’t caused a problem so it was acceptable. At one point apparently when one was burned through approximately 33% the way, a claim was made that the O-rings had a safety factor of 3. This is a gross misapplication of the concept of a safety-factor since the O-rings were specced to have zero burn-through. By moving the goalposts, they permitted further launches to occur and burnthroughs to continue to until 51L and seven lives were lost. This was a huge management error. In this case the mistake was to ignore the original rule and essentially rewrite it without adequate review. The engineers had become used to the new norm, despite it being wrong.

In the example given in the first link above, a different form of deviance occurred. This was a social deviance that apparently made the lack of use of checklists acceptable.

In the crash, a large red warning device was completely ignored. One would think this was the mistake that caused the crash. However it’s really secondary to the original problem. The original problem is that checklists were developed precisely because humans CAN fail to notice large red warning devices. By not performing the checklist a mistake was missed and lives lost. Everything else is sort of fluff.

For pilots, take-offs become a routine procedure. So routine they begin to make simple mistakes. Had this been their first time flying or even their first time in that particular model of aircraft they most certainly would have been paying attention. This is why checklists exist in cases like this, to eliminate the mistakes routine can introduce. Either pilot should have questioned the lack of the take-off checklists and insisted on their use.

Yes, the experience and calmness was a big part of it. Those came in part because of the background and training he had and because they had a checklist for most items so he could focus on flying while the First Officer could focus on other items. A good division of responsibilities.